Ultrasonic sensors have been used for many years in a wide range of applications, particularly medical imaging. Sensors manufactured as single elements and linear arrays, are often combined with some kind of scanning system to obtain additional data. The prior art shows some limited two dimensional arrays, but none incorporate a completely filled, two dimensional array of transducers.
Medical imaging technologies include B-scan ultrasound, MR imaging, nuclear medicine, CT imaging and limited C-scan techniques. The state of the art is discussed briefly below.